[Live-devel] setMediaSessionParameter Response

[Ross Finlayson]

>     I am trying write program to track switching on mp4 files.
>  Like switch resolutions on the fly.  My current plan is to
>add a parameter called track, and set it with the
>setMediaSessionParamter() function. 
>
>     However, I would like to see the response message sent by
>the server.   This is because, I want the server to respond
>with the time or position code. (I haven't defined that yet.)
>   This would allow the client to interpolate the right frame.
>  It also might allow the server to respond with new media
>information for the other track, such as, picture parameter
>set (PPS), and sequence parameter set (SPS) in mp4.

I'm not totally sure I understand your question, but once a stream 
has begun, any changes in codec parameters are best conveyed within 
the media stream itself - and therefore, of course, the client's 
decoder has to be able to handle any such dynamic changes.  In 
particular, changes to PPS and SPS are best handled by having the 
server just send new NAL units (in-band) that contain the new values.

It's not a good idea to expect the server to signal such changes back 
to the client (in the 'control channel').  Even if this were possible 
(which it's probably not), you couldn't expect many clients to be 
able to handle this anyway.
-- 

Ross Finlayson
Live Networks, Inc.
http://www.live555.com/